This invention relates to excavator bucket structure, and more particularly, to such a bucket which includes a pair of adjustable ripper assemblies built into the rear of the bucket.
The hydraulic excavator is an extremely versatile construction machine and is used in a variety of applications, such as trenching, excavating, and general construction operations. Hardened teeth are generally added to the cutting edge portion of the bucket to aid in penetrating hard or rock-filled earth. In extremely severe applications, the machine operator will sometimes operate the bucket in a chopping-type manner. This is extremely hard on the machine and machine components, and often reduces the overall life of the bucket and related components.
In an attempt to overcome this problem, various types of ripper assemblies have been added to the bucket in various locations. The most common location is one on the rear of the bucket, such that a ripping operation takes place as the bucket is moved through the earth. In most cases, the ripper or rippers are added to the back of the bucket as an attachment, by welding various types of plates and/or supports to accept the ripper shanks. The ripper shanks are generally pinned in some manner to this auxiliary structure such that they can be removed when the machine operator desires that no ripping takes place.
U.S. Pat. Nos. 3,061,123 (Rogers), 3,596,996 (Carter), and 3,702,712 (Cairns) show various ripper structures for use on backhoe buckets. In each of these patents, the ripper structure is added as an attachment to the back of the bucket. By addition of such an attachment rather than building such structure into the bucket itself, the strength of the ripper assembly would appear not to be maximized. In each case, a large moment arm is generated by the distance from the ripper tip to the attachment of the ripper shank to the assembly. When ripping, this moment arm can generate a great deal of torsion or bending which can cause overstressing of the ripper shank or mounting structure connected thereto. Such overstressing may often lead to early failure of the structure.